Investigations into the therapeutic use of radiofrequency (RF) energy in man occurred as early as the late 19th and early 20th centuries. Technological advances increased interest in RF applications. Because of its precise control of energy delivery and reliability, RF energy has been used for decades in neurosurgical techniques. (Liu J K, Apfelbaum R I, Treatment of trigeminal neuralgia. Neurosurg Clin N Amer. 2004; 15:319-34.) By the 1980s cardiac arrhythmias were being treated with RF devices. (Filingeri V, Gravante G, Cassisa D. Physics of radiofrequency in proctology, Eur Rev Med Pharmacol Sci. 2005; 9:349-54.) Usage expanded to include treatment of various malignancies, including hepatic, renal, musculoskeletal, breast, lymph, spleen, pulmonary (Brown D B. Concepts, considerations, and concerns on the cutting edge of radiofrequency ablation. J Vasc Interv Radiol. 2005; 16:597-613, and Gillams A R. The use of radiofrequency in cancer. Br J. Cancer. 2005; 92:1825-9), as well as ophthalmologic maladies, gastric reflux, sleep apnea and aesthetic dermatological conditions. (Berjano E J. Theoretical modeling for radiofrequency ablation: state-of-the-art and challenges for the future. Biomed Eng Online. 2006, Apr. 18; 5:24, and Sadick N, Sorhaindo L. The radiofrequency frontier: a review of radiofrequency and combined radiofrequency pulsed-light technology in aesthetic medicine. Facial Plast Surg. 2005; 21:131-8.) Berjano reported that the number of scientific papers published on the topic of therapeutic RF energy use increased from 19 in 1990 to 825 in 2005. (Berjano E J. Theoretical modeling for radiofrequency ablation: state-of-the-art and challenges for the future. Biomed Eng Online. 2006, Apr. 18; 5:24.) As a less invasive alternative to vein stripping for elimination of saphenous vein reflux, the percutaneous catheter-based radiofrequency Closure® procedure (VNUS Medical Technologies, San Jose, Calif.) was introduced in Europe in 1998 and in the U.S. in 1999.
Following initial experience with the Closure procedure and early technique modifications, it became clear that reflux at the saphenofemoral junction (SFJ) could be eliminated by obliteration of the great saphenous vein in the thigh without resorting to dissection and ligation of all contributing branches near the saphenofemoral junction, (Chandler J G, Pichot O, Sessa C, et al. Defining the role of extended saphenofemoral junction ligation: A prospective comparative study. J Vasc Surg. 2000; 32:941-53, and Chandler J O, Pichot O, Sessa C, et al. Treatment of primary venous insufficiency by endovenous saphenous vein obliteration. Vasc Surg. 2000; 34:201-14) thus eliminating the need for a groin incision and potential for minor and even major complications that can occur following traditional ligation and stripping procedures, and leaving intact venous return and lymphatic drainage from the abdominal wall and lower extremity. The validity of this strategy has been borne out by several published mid-term reports. (Nicolini P; Closure Group. Treatment of primary varicose veins by endovenous obliteration with the VNUS closure system: results of a prospective multicentre study. Eur J Vasc Endovasc Surg. 2005; 29:433-9; Merchant R F, Pichot O, Myers K A. Four-year follow-up on endovascular radiofrequency obliteration of great saphenous reflux. Dermatol Surg. 2005; 31:129-34; Pichot O, Kabnick L S, Cretan D, et al. Duplex ultrasound scan findings two years after great saphenous vein radiofrequency endovenous obliteration. J Vasc Surg. 2004; 39:189-95; and Lurie F, Creton D, Eklof B, et al. Prospective randomised study of endovenous radiofrequency obliteration (closure) versus ligation and vein stripping (EVOLVeS): two-year follow-up. Eur J Vasc Endovasc Surg. 2005; 29:67-73.) Pichot (Pichot O, Kabnick L S, Cretan D, at al. Duplex ultrasound scan findings two years after great saphenous vein radiofrequency endovenous obliteration. J Vasc Surg. 2004; 39:189-95) coordinated an extensive two year follow-up ultrasound evaluation study from five VNUS Registry centers. The results showed that 58/63 (92.1%) treated GSV segments remained free of reflux. Junctional tributary reflux was seen in 7/63 (11.1%) limbs, four of which were associated with the SFJ as the sole source of reflux. Neovascularization was not observed in any treated limbs. More recently, Closure equipment innovations and technique modifications have contributed to reduced procedure times while maintaining efficacy and low rates of complications.
For some closure procedures, such as the VNUS Closure procedure, a catheter with a radio-frequency (RF) heating coil may be used to close a vein within a leg of a patient. During the procedure, the heating coil must be drawn down the leg and compression must be maintained over the length of the heating coil as the patient is supported supine on a table.
Generally, it is very cumbersome to maintain this pressure and an additional technician may be necessary to maintain such pressure. The heat from the coil must also be applied for a given amount of time. This timing is generally 20 seconds for each 7 cm section of coil, with the first segment heated twice, and then periodically repositioned with pressure being regulated. This treatment may take 20 minutes to complete. Results from this procedure may be less than optimal due to the cumbersome and complex pressure maintenance and timing involved.